Pronounced: PREH-tuh-ruht, noun
Notes: I should have known this word
The word roister-doister, as a noun, means “a swaggering buffoon or reveler”. The adjective form is similar – “engaged in swaggering buffoonery”.
Background / Comments
This word comes from Ralph Roister Doister, the main character in a play written by Nicolas Udall in the mid-1500s. Roister means to behave in a boisterous, swaggering manner, and comes from Middle French rustre (boor), which itself comes from Latin rusticus (rustic).
This word entered English in the late 1500s.